Understanding Dark Current-Voltage Characteristics in Metal-Halide Perovskite Single Crystals
Understanding Dark Current-Voltage Characteristics in Metal-Halide Perovskite Single Crystals
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DOI：
10.1103/physrevapplied.15.014006
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发表时间：
2021-01-06
影响因子：
4.6
通讯作者：
Snaith, Henry J.
中科院分区：
文献类型：
--
作者：
Duijnstee, Elisabeth A.;Le Corre, Vincent M.;Snaith, Henry J.
杂化卤化物钙钛矿材料在光电子器件中具有很大的应用潜力。然而，对一些基本性质的理解，如电荷-载流子输运，仍然没有定论，这主要是由于这些材料的离子和电子性质的混合。在这里，我们进行温度相关的脉冲电压空间电荷限制电流测量，以提供对甲基铵三溴化铅(MAPbBr(3))和甲基铵三碘化铅(MAPbI(3))单晶的电子性质的详细观察。结果表明，这些晶体中的背景载流子密度比来自价带的热激发载流子密度高出几个数量级。我们通过实验和漂移扩散模拟相结合的方法强调了系统的复杂性，并表明不同的因素，如来自电极的热注入、依赖于温度的迁移率以及陷阱和离子密度，都会影响自由载流子浓度。我们实验测定了MAPbBr3的(349+/-10)meV和MAPbI(3)的(193+/-12)meV的有效电导激活能，它包含了所有这些因素的总和。我们指出，用漂移扩散模型拟合暗电流密度-电压曲线可以提取本征参数，如迁移率、陷阱和离子密度。模拟结果表明，MAPbBr(3)单晶的载流子迁移率为12.9 cm(2)/vs，陷阱密度为1.52×10(13)cm(-3)，离子密度为3.19×10(12)cm(-3)。深入了解金属卤化物钙钛矿型单晶中的载流子输运将有助于各种光电子学应用中的器件优化。
Hybrid halide perovskites have great potential for application in optoelectronic devices. However, an understanding of some basic properties, such as charge-carrier transport, remains inconclusive, mainly due to the mixed ionic and electronic nature of these materials. Here, we perform temperature-dependent pulsed-voltage space-charge-limited current measurements to provide a detailed look into the electronic properties of methylammonium lead tribromide (MAPbBr(3)) and methylammonium lead triiodide (MAPbI(3)) single crystals. We show that the background carrier density in these crystals is orders of magnitude higher than that expected from thermally excited carriers from the valence band. We highlight the complexity of the system via a combination of experiments and drift-diffusion simulations and show that different factors, such as thermal injection from the electrodes, temperature-dependent mobility, and trap and ion density, influence the free-carrier concentration. We experimentally determine effective activation energies for conductivity of (349 +/- 10) meV for MAPbBr3 and (193 +/- 12) meV for MAPbI(3), which includes the sum of all of these factors. We point out that fitting the dark current density-voltage curve with a drift-diffusion model allows for the extraction of intrinsic parameters, such as mobility and trap and ion density. From simulations, we determine a charge-carrier mobility of 12.9 cm(2)/Vs, a trap density of 1.52 x 10(13) cm(-3), and an ion density of 3.19 x 10(12) cm(-3) for MAPbBr(3) single crystals. Insights into charge-carrier transport in metal-halide perovskite single crystals will be beneficial for device optimization in various optoelectronic applications.